Evaluation aid and evaluation device

ABSTRACT

An evaluation aid is used as a phantom (imitation lesion) when a digital X-ray dynamic image thereof is taken and evaluated for image qualities for X-ray absorption parts having different X-ray absorption ratios. The evaluation aid contains a fixed plate (plate-like body) including a plurality of regions having different X-ray absorption ratios; a rotating disk (movable body) having a plurality of wires (wire rods), the rotating disk capable of rotating (moving) with respect to the fixed plate so that the plurality of wires traverse X-ray with which the fixed plate is irradiated; and a driving motor (driving portion) which rotates (moves) the rotating disk with respect to the fixed plate. It is preferred that thicknesses and/or constituent materials of the plurality of regions of the fixed plate are different from each other, so that these regions have the different X-ray absorption ratios.

This application is a continuation of U.S. application Ser. No.14/131,143, titled “EVALUATION AID AND EVALUATION DEVICE”, which claimspriority to international application No. PCT/JP2012/066884 having aninternational filing date of Jul. 2, 2012, which claims priority toJP2011-152322 filed Jul. 8, 2011, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an evaluation aid, and especially anevaluation aid adapted to be used for taking a digital X-ray dynamicimage thereof through which evaluation is carried out, and an evaluationdevice provided with such an evaluation aid.

RELATED ART

Quality control (QC) or quality assurance (QA) of a medical X-rayapparatus, or keeping an X-ray image quality in a required level is veryimportant. Further, recent X-ray apparatuses have excellentperformances, for example, X-ray apparatuses including flat paneldetectors with wide dynamic ranges are in widespread use.

Such X-ray apparatuses having excellent performances are required to bechecked in detail every day. Considering the fact that it is necessaryto check the X-ray apparatus every day, it is preferred that a checkoperation thereof can be easily carried out. As an evaluation aidcapable of easily carrying out such a check operation, there is known adigital image phantom proposed by Oda et al. (see Non-patent document1).

By using the digital image phantom of Oda et al., spatial resolution orcontrast resolution of a digital X-ray image can be evaluated.

Meanwhile, when roughly dividing a human body from the viewpoint ofdifferences of X-ray absorption ratios, it can be classified into threeparts including a high X-ray absorption part such as a bone, a middleX-ray absorption part such as an internal organ or a soft tissue and alow X-ray absorption part such as a lung (pneumatic organ).

However, in the case where the digital image phantom of Oda et al. isused, there is a problem in that an image quality of an X-ray image onlyfor one X-ray absorption part can be evaluated, but image qualities ofan X-ray image for X-ray absorption parts having different X-rayabsorption ratios cannot be evaluated at once.

Further, the Ministry of Health, Labour and Welfare of Japan notifiedthe ordinance defining safety control of medical equipment on Mar. 30,2007. Therefore, importance of the quality control or the qualityassurance of the X-ray apparatus is further increasing.

For these reasons, there is a demand for developing an evaluation aid(phantom) which can easily evaluate image qualities of an X-ray imagefor the X-ray absorption parts having different X-ray absorption ratios(detectability of imitation lesion) at once.

Further, recently, a procedure of placing a stent into a moving cardiacblood vessel and the like are sometimes performed under X-rayillumination (while displaying an X-ray dynamic image of the cardiacblood vessel and confirming it). However, an evaluation aid which caneasily and reliably evaluate image qualities of such an X-ray dynamicimage does not exist until now. Therefore, there is also a demand fordeveloping such an evaluation aid.

PRIOR ART DOCUMENT Patent Document

-   Non-patent document 1: Establishment and standardization of a    quality assurance program for computed radiography systems (report    from the scientific research group) Japanese Journal of Radiological    Technology 59(1), 97-116, 2003

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

It is an object of the present invention to provide an evaluation aidwhich can be used as a phantom (imitation lesion) when a digital X-raydynamic image thereof is taken and then evaluation is carried outthrough the digital X-ray dynamic image, and especially an evaluationaid which can be used for easily evaluating image qualities of a digitalX-ray dynamic image for X-ray absorption parts having different X-rayabsorption ratios at once, and an evaluation device provided with suchan evaluation aid.

Means for Solving Problem

In order to achieve the object, the present invention includes thefollowing features (1) to (18).

(1) An evaluation aid adapted to be used for taking a digital X-raydynamic image thereof, wherein evaluation is carried out through thedigital X-ray dynamic image, the evaluation aid comprising:

a plate-like body including a plurality of regions having differentX-ray absorption ratios;

at least one movable body having a plurality of wire rods, the movablebody capable of moving with respect to the plate-like body so that theplurality of wire rods traverse X-ray with which the plate-like body isirradiated; and

a driving portion which moves the movable body with respect to theplate-like body.

(2) The evaluation aid according to the above feature (1), whereinthicknesses and/or constituent materials of the plurality of regions ofthe plate-like body are different from each other, so that these regionshave the different X-ray absorption ratios.

(3) The evaluation aid according to the above feature (1) or (2),wherein the plate-like body is formed by laminating plate members havingdifferent planar sizes together, and

wherein thicknesses of the plurality of regions of the plate-like bodyare different from each other due to differences of the number of theplate members contained therein, so that these regions have thedifferent X-ray absorption ratios.

(4) The evaluation aid according to any one of the above features (1) to(3), wherein the plate-like body is formed of a material containingcopper as a major component thereof.

(5) The evaluation aid according to any one of the above features (1) to(4), wherein a moving speed of the movable body with respect to theplate-like body is changeable.

(6) The evaluation aid according to any one of the above features (1) to(5), wherein a moving direction of the movable body with respect to theplate-like body is changeable.

(7) The evaluation aid according to any one of the above features (1) to(6), wherein the movable body is rotatably provided with respect to theplate-like body.

(8) The evaluation aid according to the above feature (7), wherein arotating speed of the movable body with respect to the plate-like bodyis in the range of 25 to 40 revolutions per minute.

(9) The evaluation aid according to any one of the above features (1) to(8), wherein the plurality of wire rods are arranged at substantiallyeven intervals.

(10) The evaluation aid according to any one of the above features (1)to (9), wherein cross-sectional areas of the plurality of wire rods aredifferent from each other.

(11) The evaluation aid according to any one of the above features (1)to (10), wherein each wire rod is formed of a material containing iron,carbon, silicon, manganese, or two or more of them as a major componentthereof.

(12) The evaluation aid according to any one of the above features (1)to (11), wherein the movable body is formed by fixing the plurality ofwire rods to a sheet material.

(13) The evaluation aid according to the above feature (12), wherein anX-ray absorption ratio of a constituent material of the sheet materialis lower than X-ray absorption ratios of constituent materials of theplate-like body and each wire rod.

(14) The evaluation aid according to the above feature (12) or (13),wherein the sheet material is formed from a paper fibrous base materialinto which epoxy resin is impregnated.

(15) The evaluation aid according to any one of the above features (1)to (14), wherein the at least one movable body includes a plurality ofmovable bodies having different structures, the plurality of movablebodies are replaceable.

(16) The evaluation aid according to the above feature (15), wherein inat least one of the plurality of movable bodies, at least one of theplurality of wire rods is segmented into line segments.

(17) The evaluation aid according to the above feature (15) or (16),wherein at least one of the plurality of movable bodies further includesa part constituted from a material having an X-ray absorption ratiolower than an X-ray absorption ratio of a constituent material of eachwire rod.

(18) An evaluation device comprising:

the evaluation aid defined by any one of the above features (1) to (17);and

a controlling unit which is connected to the evaluation aid and controlsdriving thereof.

Effects of the Invention

According to the present invention, it is possible to easily andreliably carry out evaluation and quality control (QC) or qualityassurance (QA) of an X-ray apparatus through a digital X-ray dynamicimage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an embodiment of an evaluationdevice of the present invention.

FIG. 2 is a side view showing the evaluation aid shown in FIG. 1.

FIG. 3 is a cross-sectional view of the evaluation device along the lineA-A in FIG. 1.

FIG. 4 is a planar view showing the base of the evaluation aid shown inFIG. 1.

FIG. 5 is a planar view showing another structural example of therotating disk of the evaluation aid shown in FIG. 1.

FIG. 6 is a planar view showing another structural example of therotating disk of the evaluation aid shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, detailed description will be made on an evaluation aid andan evaluation device of the present invention based on a preferredembodiment described in the accompanying drawings.

FIG. 1 is a perspective view showing an embodiment of an evaluationdevice of the present invention, FIG. 2 is a side view showing theevaluation aid shown in FIG. 1, FIG. 3 is a cross-sectional view of theevaluation device along the line A-A in FIG. 1, FIG. 4 is a planar viewshowing the base of the evaluation aid shown in FIG. 1, FIGS. 5 and 6are planar views each showing another structural example of the rotatingdisk of the evaluation aid shown in FIG. 1.

An evaluation device 10 shown in FIG. 1 is used for taking a digitalX-ray dynamic image (hereinafter, simply referred to as “X-ray dynamicimage”) thereof through which evaluation is carried out when conditionsof an X-ray apparatus used for taking the X-ray dynamic image are to bechecked. This evaluation device 10 includes an evaluation aid (phantom)1 and a controlling unit 8 which controls driving of the evaluation aid1.

According to such an evaluation device 10, after placing the evaluationaid 1 on the X-ray apparatus, an X-ray dynamic image of the evaluationaid 1 is taken by the X-ray apparatus. If the X-ray dynamic image doesnot have required image qualities, a condition of the X-ray apparatus isdetermined to be unusual and therefore it can be appropriately adjusted.This makes it possible for the X-ray apparatus to constantly provide anX-ray dynamic image having required image qualities (resolution).Therefore, it is possible to reliably prevent occurrence of medicalaccidents by poor X-ray dynamic images. As a result, it becomes possibleto diagnose and treat diseases accurately.

In this regard, examples of the X-ray dynamic image include an X-raydynamic image by perspective imaging, an X-ray dynamic image byconsecutive imaging, an X-ray dynamic image by cine imaging and thelike.

The evaluation aid 1 includes a base 2, a driving motor (drivingportion) 3 provided on the base 2, a rotating disk 4 fixed to thedriving motor 3 and an electrical wiring 7 which connects thecontrolling unit 8 to the driving motor 3.

The base 2 has a base plate 21, a motor housing 22 provided on the baseplate 21 for receiving the driving motor 3, an attaching plate 23 whichsecures the driving motor 3 received in the motor housing 22 thereto, afixed plate 24 provided on the base plate 21 along an outer periphery ofthe motor housing 22.

The base plate 21 is a part supporting other parts of the evaluation aid1 and is formed from a disk-shaped member. A planar size of the baseplate 21 is preferably set depending on a size of a desired (imaging)target area or a detector of the X-ray apparatus, for example, to about30 to 100 mm in radius. Especially, in the case where the desired(imaging) target area is a cardiovascular area, the radius of the baseplate 21 is preferably set to about 50 to 70 mm.

The motor housing 22 is provided on an almost central portion of thebase plate 21 so as to be perpendicular to the base plate 21. The motorhousing 22 is formed from a cylindrical member having an inner cavity221. The driving motor 3 is received in this inner cavity 221.

Further, a diameter of the inner cavity 221 of the motor housing 22 isreduced in middle of a height direction thereof. As a result, a step 222is formed along an inner surface of the motor housing 22 (see FIG. 3).This step 222 serves as a pedestal to which an outer periphery of thedriving motor 3 is locked.

In this embodiment, the motor housing 22 and the base plate 21 areintegrally formed with each other, but they may be separately formedfrom each other and then fixed or bonded to each other.

The attaching plate 23 is fixed on an upper surface of the motor housing22. This attaching plate 23 is formed from a disk-shaped member. Athrough hole 231, through which a rotating shaft 32 of the driving motor3 is passed, is formed at an almost central portion of the attachingplate 23.

The driving motor 3 is received in the motor housing 22, the rotatingshaft 32 is passed through the through hole 231, and then the attachingplate 23 is fixed to the motor housing 22. In this way, a main body 31of the driving motor 3 is nipped with the step 222 and the attachingplate 23 so that the driving motor 3 is fixed with respect to the motorhousing 22 (base 2).

Examples of a constituent material of such a base 2 (each of the baseplate 21, the motor housing 22 and the attaching plate 23) include, forexample, various kinds of resin materials or various kinds of metalmaterials.

Further, the fixed plate (plate-like body) 24 is placed on the baseplate 21 so as to be provided concentrically with respect to the motorhousing 22 (driving motor 3). In this regard, it is noted that the fixedplate 24 may be fixed to the base plate 21 using a method such as awelding method, a fusing method or a bonding method with an adhesiveagent.

The evaluation device 10 is used by placing the base plate 21 on theX-ray apparatus at a side of the detector thereof. Therefore, when X-rayis emitted from an X-ray emitter to the detector, the X-ray is incidenton the fixed plate 24 on the base plate 21, and then passes through thefixed plate 24 and/or is absorbed by the fixed plate 24, to thereby takean X-ray image.

As shown in FIGS. 1 to 4, the fixed plate 24 is formed by laminating aplurality of (in this embodiment, three) plate members 241 to 243together.

Further, planar sizes of the plate members 241 to 243 are different fromeach other. Specifically, the plate member 241 is formed from a memberhaving a ring-like planar shape, the plate member 242 is formed from amember having such a planar shape that a fan-like portion is removedfrom a ring, and the plate member 243 is formed from a member having afan-like planar shape. In this regard, it is to be noted that radii ofthe respective plate members 241 to 243 are substantially similar toeach other.

According to such a structure, the fixed plate 24 includes a region Aformed by overlapping three plate members 241 to 243, a region B formedby overlapping two plate members 241 and 242, and a region C formed byone plate member 241 (see FIGS. 2 and 4). Therefore, as shown in FIG. 2,thicknesses of the regions A to C are different from each other due todifferences of the number of the plate members 241 to 243 containedtherein. As a result, the region A has the thickness of “TA”, the regionB has the thickness of “TB” and the region C has the thickness of “TC”,respectively.

In this embodiment, the plate members 241 to 243 are formed of the samematerial. As a result, the regions A to C have different X-rayabsorption ratios, respectively. The region A has a maximum X-rayabsorption ratio by setting the thickness “TA” thereof to a maximumvalue, the region C has a minimum X-ray absorption ratio by setting thethickness “TC” thereof to a minimum value, and the region B has a mediumX-ray absorption ratio between the X-ray absorption ratio of the regionA and the X-ray absorption ratio of the region C by setting thethickness “TB” thereof to a value between the thickness “TA” of theregion A and the thickness “TC” of the region C, respectively.

According to such a structure, the region A can be considered to be ahigh X-ray absorption part of a human body such as a bone, the region Bcan be considered to be a middle X-ray absorption part such as aninternal organ or a soft tissue, and the region C can be considered tobe a low X-ray absorption part such as a lung (pneumatic organ),respectively. Therefore, by using such an evaluation aid 1, imagequalities of an X-ray dynamic image for three X-ray absorption partsincluding the high X-ray absorption part, the middle X-ray absorptionpart and the low X-ray absorption part can be evaluated at once, andthus this is advantageous.

Further, it is preferred that the fixed plate 24 (that is, each of theplate members 241 to 243) is constituted from a material having arelatively high X-ray absorption ratio, e.g., a material containingcopper, tungsten, lead, titanium, iron, stainless steel, tin or the likeas a major component thereof. Among them, it is preferred that the fixedplate 24 is constituted from the material containing copper as the majorcomponent thereof. This is because copper is comparatively inexpensiveand has good workability and excellent safeness for living body.

The thicknesses of the regions A to C are not limited to specific valuesas long as they are set so that the regions A to C have differentpredetermined X-ray absorption ratios. In the case where the fixed plate24 is constituted from copper, the thicknesses of the regions A to C arepreferably set to the following values, respectively. Namely, thethickness “TA” of the region A is preferably in the range of about 0.5to 7 mm, and more preferably in the range of about 1 to 5 mm. Thethickness “TB” of the region B is preferably in the range of about 0.1to 5 mm, and more preferably in the range of about 0.5 to 3 mm. Thethickness “TC” of the region C is preferably in the range of about 0.05to 3 mm, and more preferably in the range of about 0.1 to 2 mm.

In this embodiment, the X-ray absorption ratios of the regions A to Care set to the different values by changing the thickness of the fixedplate 24 (that is, the thickness of the regions A to C). However, theX-ray absorption ratios of the regions A to C may be set to thedifferent values by changing the constituent materials thereof, or bychanging the thicknesses thereof as well as the constituent materialsthereof. In this regard, in the case where the X-ray absorption ratiosof the regions A to C are set to the different values by changing theconstituent materials thereof, an entire thickness of the fixed plate 24may be set to a constant value. This makes it possible to obtain anevaluation aid 1 having a thinner thickness.

Further, the fixed plate 24 can be formed by not laminating theplurality of plate members 241 to 243 together, that is, may be alsoformed from a single plate member 241 having a ring-like planar shape.In this case, it is also possible to evaluate an image quality of anX-ray dynamic image for one part (organ) having a single X-rayabsorption ratio.

Furthermore, an angle between end sides of the plate member 242 (θ1shown in FIG. 4) is, in this embodiment, set to about 240°, but is notlimited thereto, preferably set within a range of about 200 to 260°. Anangle between end sides of the plate member 243 (angle θ2 shown in FIG.4) is, in this embodiment, set to about 120°, but is not limitedthereto, preferably set within a range of about 100 to 140°.

The rotating disk 4 is fixed to the rotating shaft 32 of the drivingmotor 3. In this way, the rotating disk 4 becomes able to be rotated(moved) with respect to the base 2.

The rotating disk 4 has a rotating disk main body (movable body) 5 and afixing portion 6 for fixing the rotating disk main body 5 to therotating shaft 32 of the driving motor 3.

A through hole 53 is formed at an almost central portion of the rotatingdisk main body 5, and the fixing portion 6 has a fixing portion mainbody 61 to be passed through the through hole 53 of the rotating diskmain body 5. This fixing portion main body 61 is formed from acylindrical member with a bottom, and the rotating shaft 32 of thedriving motor 3 is inserted into an inner cavity of the fixing portionmain body 61.

A ring-shaped flange 62 is integrally formed with the fixing portionmain body 61 at a lower end part thereof. The fixing portion main body61 is passed through the through hole 53 of the rotating disk main body5, the flange 62 makes contact with a lower surface of the rotating diskmain body 5, and then the contact portions thereof are bonded togetherby fusing, bonding with an adhesive agent or the like. In this way, thefixing portion 6 is fixed to the rotating disk main body 5.

Further, a screw hole 611 is formed at a bottom part (upper part) of thefixing portion main body 61, a screw part 631 of a screw 63 for heightadjustment is screwed to and passed through the screw hole 611. In astate that the screw part 631 of the screw 63 is screwed to and passedthrough the screw hole 611, a lower end of the screw part 631 makescontact with an upper end of the rotating shaft 32 of the driving motor3.

Therefore, by rotating and operating a screw head 632 of the screw 63,it is possible to adjust a projecting length of the screw part 631 inthe inner cavity of the fixing portion main body 61. This makes itpossible to adjust a vertical position of the rotating disk main body 5with respect to the driving motor 3, that is, a distance between therotating disk main body 5 and the fixed plate 24.

It is preferred that the distance between the rotating disk main body 5and the fixed plate 24 (minimum distance D shown in FIG. 3) is as shortas possible from the viewpoint of downsizing the evaluation aid 1. Thedistance is not limited to a specific value, but is preferably 60 mm orless, more preferably 40 mm or less, and even more preferably 20 mm orless.

On the other hand, a screw hole 612 is formed at a side part of thefixing portion main body 61, a screw 64 for fixation is screwed to andpassed through the screw hole 612. In a state that the screw 64 isscrewed to and passed through the screw hole 612, a left end of thescrew 64 makes contact with a side surface of the rotating shaft 32 ofthe driving motor 3.

Therefore, by tightening the screw 64 in a state that the rotating shaft32 of the driving motor 3 is inserted in the inner cavity of the fixingportion main body 61, it is possible to fix the fixing portion 6(rotating disk 4) with respect to the rotating shaft 32 of the drivingmotor 3.

Further, examples of a constituent material of the fixing portion 6(each of the fixing portion main body 61, the flange 62, the screw 63and the screw 64) include, for example, various kinds of resin materialsor various kinds of metal materials.

The rotating disk main body 5 fixed to such a fixing portion 6 includesa plurality of (in this embodiment, 8) wires (wire rods) 511 to 518radially arranged, and two sheet materials 52 between which each of thewires 511 to 518 is fixed by being sandwiched. Each of the wires 511 to518 is mainly used for evaluating contrast resolution and spatialresolution of the obtained X-ray dynamic image for each of the regions Ato C having different X-ray absorption ratios.

By rotating the rotating disk main body 5 with respect to the base 2,each of the wires 511 to 518 is moved above the fixed plate 24 (betweenthe fixed plate 24 and the X-ray emitter of the X-ray apparatus) so asto traverse the X-ray from the X-ray emitter with which the fixed plate24 is irradiated. Therefore, by consecutively taking an X-ray image,that is, by taking an X-ray dynamic image, each of the wires 511 to 518becomes observed so as to pass through each of the regions A to C in theobtained X-ray dynamic image.

Further, each of the wires 511 to 518 is formed from a wire rod having acircular cross-section. These wires 511 to 518 have different diameters(cross-sectional areas), respectively. In this embodiment, a diameter ofthe wire 511 is minimum, diameters of the wires 512 to 518 increasegradually from the wire 512 to the wire 518, and a diameter of the wire518 is maximum.

Due to these different diameters, an X-ray absorption ratio of the wire511 is minimum, X-ray absorption ratios of the wires 512 to 518 increasegradually from the wire 512 to the wire 518, and an X-ray absorptionratio of the wire 518 is maximum. Therefore, for example, in the casewhere the wire 515 is not clearly observed in an area of the X-raydynamic image corresponding to the region A of the fixed plate 24 evenif the evaluation aid 1 is irradiated with X-ray having such intensitythat the wires 515 to 518 are to be clearly observed, this means thatthe intensity of the X-ray is higher than a predetermined intensitythereof or inadequate (or sensibility change of the detector of theX-ray apparatus occurs or a condition of an image display monitor isinadequate). In this way, it can be determined that adjustment of theX-ray apparatus is necessary.

Further, in the case where a rotating speed of the rotating disk 4 withrespect to the fixed plate 24 (rotating speed of the driving motor 3) isset so as to correspond to, for example, a heart rate of a heart, anX-ray image of a predetermined wire in an area of the X-ray dynamicimage corresponding to the region B of the fixed plate 24 (in thisembodiment, corresponding to the middle X-ray absorption part) can beconsidered to be an X-ray image of a guide wire inserted in a cardiacblood vessel.

In the case where the rotating speed is matched with the heart rate(moving speed) of the heart, such a rotating speed is preferably in therange of about 25 to 40 revolutions per minute, and more preferably inthe range of about 30 to 35 revolutions per minute. In this regard,according to the present invention, it is sufficiently possible to matchthe rotating speed with a high heart rate of a heart of child or thelike. Further, in the case where other moving organs or a blood flow istargeted, the rotating speed may be set depending on moving speeds ofthe other moving organs or the like. Examples of the other moving organsinclude, for example, a lung, a diaphragm, an abdominal organ (includinga gastrointestinal gas) and the like.

The diameter of each of the wires 511 to 518 is preferably set within arange of about 0.01 to 3 mm, and more preferably within a range of about0.05 to 1.5 mm.

A cross-sectional shape of each of the wires 511 to 518 is not limitedto a circular shape, but may be an ellipsoidal shape, a quadrangularshape such as a rectangle shape or a square shape, or a polygonal shapesuch as a triangular shape, a pentagonal shape or a hexagonal shape.

In this embodiment, the wires 511 to 518 are arranged at substantiallyeven intervals. However, they may be not arranged at the even intervals.

For example, each of the wires 511 to 518 can be used by cutting a pianowire, a guide wire or the like. It is preferred that each of the wires511 to 518 is formed of a material containing iron, carbon, silicon,manganese, or two or more of them (e.g., alloy) as a major componentthereof.

Each of the wires 511 to 518 is fixed between the two sheet materials 52by bonding them using a method such as a fusing method or a bondingmethod with an adhesive agent.

Further, it is preferred that a constituent material of the sheetmaterial 52 is hard and has an X-ray absorption ratio lower than theX-ray absorption ratios of the constituent materials of the fixed plate24 and each of the wires 511 to 518. This makes it possible to reliablyfix the wires 511 to 518 between the two sheet materials 52 and toprevent the sheet materials 52 from interfering with the evaluationthrough the X-ray dynamic image.

Examples of the sheet material 52 include a base material made of asynthetic resin, a fibrous base material, a fibrous base material intowhich a synthetic resin is impregnated, and the like. In this regard,examples of the synthetic resin include various kinds of thermoplasticresins such as polyolefin (e.g., polyethylene or polypropylene),polyamide, polyester, polyphenylene sulfide, polycarbonate, polymethylmethacrylate and polyether; various kinds of thermosetting resins suchas epoxy resin, and acrylic resin; various kinds of thermoplasticelastomers; and the like. Further, examples of the fibrous base materialinclude a paper fibrous base material, a carbon fibrous base material, aglass fibrous base material and the like.

Among them, it is preferred that the sheet material 52 is formed from apaper fibrous base material into which the epoxy resin is impregnated(paper epoxy sheet). Use of the paper fibrous base material into whichthe epoxy resin is impregnated makes it possible to prevent an X-rayabsorption ratio of the rotating disk main body 5 from increasing.Further, the paper fibrous base material into which the epoxy resin isimpregnated has advantages in that it can be easily processed ascompared to another base material and can be manufactured at a low cost.

In this regard, the rotating disk main body 5 may be formed by fixingeach of the wires 511 to 518 on an upper surface or a lower surface of asingle sheet material 52.

The controlling unit 8 is connected to the driving motor 3, which canrotatably drive such a rotating disk main body 5 (rotating disk 4),through the electrical wiring 7.

The controlling unit 8 includes an unit main body 81 in which anelectrical circuit (controlling circuit) not shown is provided, a switch82 provided on a left side of a front surface of the unit main body 81,a switch 83 provided on a right side of the front surface, a rotary knob84 provided on a central portion of the front surface, and a battery box85 provided on a rear surface of the unit main body 81.

The switch 82 is a switch for changing an on-off state of thecontrolling unit 8. By operating the switch 82 up and down, anelectrical power is supplied to the evaluation aid 1 (driving motor 3)from the controlling unit 8 through the electrical wiring 7.

On the other hand, the switch 83 is a switch for changing a rotatingdirection (moving direction) of the driving motor 3 (rotating disk 4).By operating the switch 83 up and down, it is possible to change therotating direction of the driving motor 3, that is, the rotatingdirection (moving direction) of the rotating disk 4 between a clockwiserotation (positive rotation) and a counterclockwise rotation (negativerotation).

Further, the rotary knob 84 is a switch for changing the rotating speedof the driving motor 3 (rotating disk 4). By adjusting a rotationalangle of the rotary knob 84, it is possible to set (control) therotating speed of the driving motor 3, that is, the rotating speed(moving speed) of the rotating disk 4.

A plurality of batteries, which serve as a source of electrical energy,are loaded in the battery box 85. The electrical power is supplied tothe driving motor 3 from the batteries.

By using such a controlling unit 8, it is possible to change therotating speed of the rotating disk 4. This makes it possible to takeX-ray dynamic images considered as to be moving of various kinds oforgans in a human body and carry out evaluations through the X-raydynamic images. Further, since the rotating direction of the rotatingdisk 4 can be changed, it is possible to take an X-ray dynamic imagemore exactly corresponding to each organ as compared with a case ofrotating the rotating disk 4 in a constant direction and carry outdetailed evaluation through such an X-ray dynamic image.

Especially, the rotating disk 4 can be moved like a pendulum bycontinuously and alternately changing the rotating direction of therotating disk 4, that is, by changing (switching) between the clockwiserotation and the counterclockwise rotation. This makes it possible totake an X-ray dynamic image with changing an acceleration of therotating disk 4 (phantom). Therefore, it is possible to take an X-raydynamic image more similar to moving of a human body as compared with acase of rotating the rotating disk 4 at a constant speed and carry outdetailed evaluation through such an X-ray dynamic image.

Further, by constituting the evaluation aid 1 as a battery drive systemlike this embodiment, an entire size of the evaluation device 10 becomescompact. This provides an advantage in that the evaluation device 10 canbe easily carried.

Especially, in the evaluation device 10 according to this embodiment,the evaluation is carried out through an X-ray dynamic image taken in anarea where the rotating disk main body 5 and the fixed plate 24 areoverlapped to each other at a planar view (top view) thereof. Whentaking the X-ray dynamic image, there are not any members eachdisturbing it in the above area (between the rotating disk main body 5and the fixed plate 24). Therefore, by using the evaluation device 10according to this embodiment, it is possible to carry out more reliableevaluation through the obtained X-ray dynamic image.

For example, evaluation is carried out through an X-ray dynamic image ofsuch an evaluation aid 1 provided in the evaluation device 10, asfollows.

First, the evaluation aid 1 is placed on an X-ray apparatus so that thebase plate 21 is positioned at a side of a detector thereof, and thenthe rotating disk 4 is rotated. Thereafter, an X-ray is continuouslyemitted from an X-ray emitter of the X-ray apparatus to the detectorthereof to thereby take an X-ray dynamic image of the evaluation aid 1.

Next, within areas of the obtained X-ray dynamic image corresponding tothe regions A to C of the evaluation aid 1, it is checked whether or notpredetermined wires can be observed. Further, it is also checked how thepredetermined wires are periodically observed in the respective areas.

At this time, in the case where an X-ray dynamic image having requiredcontrast resolution and spatial resolution is obtained, it can bedetermined that a condition of the X-ray apparatus is normal. On theother hand, in the case where an X-ray dynamic image not having therequired contrast resolution and/or spatial resolution is obtained, itis determined that the condition of the X-ray apparatus is unusual, andtherefore it can be adjusted so as to obtain an X-ray dynamic imagehaving predetermined image qualities.

Further, if needed, a rotating speed and/or rotating direction of therotating disk 4 may be appropriately changed (set). This makes itpossible to take a required X-ray dynamic image to thereby more reliablyevaluate through the X-ray dynamic image.

In addition, the evaluation aid 1 of this embodiment includes otherrotating disks 4′, 4″ as shown in FIGS. 5 and 6.

The rotating disk 4′ has the same structure as the rotating disk 4except that each of the wires 511 to 518 is segmented into a pluralityof (in this embodiment, 3) line segments 51 a to 51 c. Even if therotating disk 4′ is rotated at a constant speed, in each of the wires(wire rods) 511 to 518, a rotating speed of a part near a centralportion of the rotating disk 4′ is slower than a rotating speed of apart far from the central portion. Namely, even if the rotating disk 4′is rotated at the constant speed, a rotating speed of the line segment51 a is a slow speed, a rotating speed of the line segment 51 b is anintermediate speed, and a rotating speed of the segment 51 c is a fastspeed. Therefore, by segmenting each of the wires 511 to 518 into theplurality of line segments 51 a to 51 c, it becomes possible to visuallyevaluate contrast resolution and/or spatial resolution of the X-raydynamic image at the respective speeds (low, intermediate and fast) inan easy manner.

In an X-ray dynamic image taken by using such a rotating disk 4′, bychecking that the line segments 51 a to 51 c are observed integrally orseparately, it also becomes possible to evaluate spatial resolution ofthe X-ray dynamic image for the regions A to C having the differentX-ray absorption ratios. That is, it becomes possible to more correctlycarry out evaluation through the X-ray dynamic image.

In this case, a distance “d” between the line segments 51 a to 51 c ispreferably in the range of about 1 to 10 mm, and more preferably in therange of about 3 to 7 mm.

The rotating disk 4′ has small disks 519 a to 519 h each constitutedfrom a material whose X-ray absorption ratio is lower than the X-rayabsorption ratio of a constituent material of each of the wires 511 to518 in addition to the wires 511 to 518.

For example, in the case where an X-ray image of each of the wires 511to 518 is considered to be an X-ray image of a guide wire inserted in acardiac blood vessel during PCI (coronary angioplasty with catheter), anX-ray image of each of the small disks 519 a to 519 h can be consideredto be an X-ray image (sickly shadow) of a coronary dissociation whichwould lead to a problem during the PCI, that is, it can reproduce anX-ray image of an imitation lesion.

In this regard, it is preferred that the constituent material of each ofthe small disks 519 a to 519 h has an X-ray absorption ratio higher thanthe X-ray absorption ratio of the constituent material of the sheetmaterial 52. In this case, as each of the small disks 519 a to 519 h,for example, a metal plate or metal foil constituted from copper,aluminum or the like as a main component thereof can be used. Further,as the constituent material of each of the small disks 519 a to 519 h, amaterial whose X-ray absorption ratio is similar to the X-ray absorptionratio of the constituent material of the sheet material 52 may be used.In this case, as each of the small disks 519 a to 519 h, a resin plateor resin film constituted from various kinds of synthetic resinmaterials as a main component thereof can be used.

Further, the shape of the above part (imitation lesion) is not limitedto the circular shape, but may be a triangular shape, a quadrangularshape, an irregular shape (arbitrary shape) and the like.

Furthermore, each of the small disks 519 a to 519 h may be alsosandwiched between the two sheet materials 52 just like each of thewires 511 to 518 or fixed on an upper surface or a lower surface of therotating disk main body 5.

In this embodiment, these rotating disks 4, 4′, 4″ are replaceable, andcan be selectively used depending on purpose of evaluation to be carriedout through an X-ray dynamic image.

Further, a single rotating disk may have a combination of 2 or morearbitrary structures of the above rotating disks 4, 4′, 4″. For example,in the rotating disk 4, 4″, 1 to 7 wires (wire rods) can be segmentedinto line segments.

As described above, according to the present invention, it is possibleto accurately and reliably evaluate contrast resolution and/or spatialresolution of an X-ray dynamic image for a plurality of X-ray absorptionparts having different X-ray absorption ratios at once. Therefore, it ispossible to reliably prevent occurrence of medical accidents by poorX-ray dynamic images. As a result, it becomes possible to diagnose andtreat diseases accurately.

While the evaluation aid and evaluation device of the present inventionhave been described based on the embodiment shown in the drawingshereinabove, the present invention shall not be limited thereto. Eachstructure constituting the evaluation aid and evaluation device may besubstituted with an arbitrary structure having the same function as it.Further, arbitrary structures also may be added thereto.

For example, in the above embodiment, the fixed plate 24 includes threeregions having different X-ray absorption ratios, but may include tworegions or four or more regions depending on purpose thereof. Such astructure can be obtained by making the plate members constituting thefixed plate replaceable, and changing the number of the plate members,the shapes thereof, the thicknesses thereof, the constituent materialsthereof and the like.

Further, in the above embodiment, the regions having the different X-rayabsorption ratios are circularly arranged, but may be linearly arrangedalong one direction. In the latter case, the plurality of wires (wirerods) can be displaced (moved) with being circulated or shuttled aboveeach of the regions.

Furthermore, in the above embodiment, the driving portion of theevaluation aid is electrically driven, but may be mechanically driven.

Moreover, in the above embodiment, the controlling unit and theevaluation aid are separated from each other, but the controlling unitand the electrical source (battery) may be provided in the evaluationaid itself.

EXPLANATIONS OF LETTERS OR NUMERALS

-   -   1 Evaluation aid    -   10 Evaluation device    -   2 Base    -   21 Base plate    -   22 Motor housing    -   221 Inner cavity    -   222 Step    -   23 Attaching plate    -   24 Fixed plate    -   241 to 243 Plate member    -   A to C Region    -   3 Driving motor    -   31 Main body    -   32 Rotating shaft    -   4, 4′, 4″ Rotating disk    -   5 Rotating disk main body    -   511 to 518 Wire    -   51 a to 51 c Line segment    -   519 a to 519 h Small disk    -   52 Sheet material    -   53 Through hole    -   6 Fixing portion    -   61 Fixing portion main body    -   611, 612 Screw hole    -   62 Flange    -   63 Screw    -   631 Screw part    -   632 Screw head    -   64 Screw    -   7 Electrical wiring    -   8 Controlling unit    -   81 Unit main body    -   82, 83 Switch    -   84 Rotary knob    -   85 Battery box    -   D, d Distance    -   TA, TB, TC Thickness

What is claimed is:
 1. An evaluation aid adapted to be used for taking adigital X-ray dynamic image thereof, wherein evaluation is carried outthrough the digital X-ray dynamic image, the evaluation aid comprising:a driving portion having a rotational axis, a housing that receives thedriving portion therein, a plate-like body provided along an outerperiphery of the housing, the plate-like body including a plurality ofregions having different X-ray absorption ratios; and a rotating diskdetachably connected to the rotational axis of the driving portion, therotating disk having a plurality of wire rods, the rotating disk capableof rotating due to a rotation of the rotational axis so that theplurality of wire rods traverse X-ray with which the plate-like body isirradiated.
 2. The evaluation aid as claimed in claim 1, whereinthicknesses and/or constituent materials of the plurality of regions ofthe plate-like body are different from each other, so that these regionshave the different X-ray absorption ratios.
 3. The evaluation aid asclaimed in claim 1, wherein the plate-like body is formed by laminatingplate members having different planar sizes together, and whereinthicknesses of the plurality of regions of the plate-like body aredifferent from each other due to differences of the number of the platemembers contained therein, so that these regions have the differentX-ray absorption ratios.
 4. The evaluation aid as claimed in claim 1,wherein a rotating speed of the rotating disk is changeable.
 5. Theevaluation aid as claimed in claim 1, wherein a rotating direction ofthe rotating disk is changeable.
 6. The evaluation aid as claimed inclaim 1, wherein a rotating speed of the rotating disk is in the rangeof 25 to 40 revolutions per minute.
 7. The evaluation aid as claimed inclaim 1, wherein the plurality of wire rods are arranged atsubstantially even intervals.
 8. An evaluation device comprising: theevaluation aid defined by claim 1; and a controlling unit which isconnected to the evaluation aid and controls driving thereof.
 9. Theevaluation device as claimed in claim 8, wherein the evaluation aidfurther comprising a base plate fixed to the housing and supporting theplate-like body, and an electrical wiring provided on an opposite sideof the base plate from the rotating disk and connecting the drivingportion with the controlling unit.